Search Results

Background: Our study aimed to evaluate the efficacy and feasibility of neoadjuvant anti–PD-1 treatment for localized mismatch repair–deficient (dMMR) colorectal cancer (CRC). Patients and Methods: The study cohort included patients with localized dMMR CRC who received PD-1 inhibitors as neoadjuvant therapy from 3 medical centers in Southern China. Main eligibility criteria included age between 18 and 75 years, ECOG performance status of 0 or 1, and receipt of ≥2 doses of PD-1 inhibitors. Results: A total of 73 patients were included. Most of the tumors were locally advanced, including 19 (26.0%) T4a and 29 (39.7%) T4b. Most patients (79.5%) received PD-1 inhibitor monotherapy. Objective response per radiologic assessment was achieved in 62 (84.9%) patients, including 17 (23.3%) with complete response (CR) and 45 (61.6%) with partial response, with a median time to response of 9.6 weeks. Patients with T4a/4b disease had a similar response rate as those with T2–3 disease (84.0% vs 85.4%; P=.999). As of writing, a total of 50 patients have undergone surgery. Pathologic CR was achieved in most (57.1%) patients and remained high (59.5%) even among the 38 patients with T4a/4b disease. The 17 patients with CR did not undergo surgery and adopted a watch-and-wait strategy. After a median follow-up of 17.2 months (range, 3.4–45.1 months), the overall median recurrence-free and overall survivals were not reached. Among patients undergoing surgery or achieving CR, the 2-year tumor-specific disease-free and overall survival rates were both 100%. During neoadjuvant treatment, grade 3–4 adverse events occurred in 8 patients; 4 required acute intervention. Severe postoperative complications were recorded in 4 patients, 3 of whom required a second surgery. Conclusions: Neoadjuvant therapy with PD-1 blockade is highly effective for localized dMMR CRC, with an acceptable safety profile and low recurrence rate. This treatment holds promise for becoming the new standard of care for localized dMMR CRCs.

Background: Head and neck adenoid cystic carcinoma (ACC) is a rare malignant tumor that is prone to local recurrence. The NCCN Guidelines for Head and Neck Cancers recommend that all patients with ACC receive postoperative radiotherapy (PORT). However, whether PORT can improve local control and which patients can benefit from PORT are unknown. This study aimed to assess the role of PORT and provide individualized suggestions for postoperative therapy in patients with ACC. Patients and Methods: We retrospectively reviewed patients with nonmetastatic head and neck ACC who underwent surgery with or without PORT. Recursive partitioning analysis (RPA) was performed to categorize the patients and predict local recurrence-free survival (LRFS). The survival outcome was compared between non-PORT and PORT groups. Results: A total of 319 patients were included. PORT was identified as a prognostic factor for LRFS in univariate (P=.01) and multivariate analysis (P<.01). However, it did not improve distant metastasis-free survival, disease-free survival, or overall survival in univariate analysis. RPA categorized patients into 3 prognostic groups: low-risk (negative margin, T1–T2, primary location = major or minor salivary gland), intermediate-risk (negative margin, T1–T2, primary location = other locations instead of a major or minor salivary gland; negative margin, T3–T4; positive margin, without bone invasion), and high-risk (positive margin, with bone invasion). Significant LRFS improvements in the PORT group were observed among intermediate-risk (P<.01) and high-risk patients (P<.05). LRFS improvements among low-risk patients were relatively insignificant (P=.10). Conclusions: PORT was shown to be a positive prognostic factor for improved LRFS in ACC. Furthermore, PORT could significantly improve LRFS in intermediate-risk and high-risk patients with ACC, but whether low-risk patients could benefit from PORT needs further study.

Background: Differences between the features of primary cancer and matched metastatic cancer have recently drawn attention in research. This study investigated the concordance in microsatellite instability (MSI) and mismatch repair (MMR) status between primary and corresponding metastatic colorectal cancer (CRC). Methods: Consecutive patients with metastatic CRC who had both primary and metastatic tumors diagnosed at our institution in January 2008 through December 2016 were identified. Immunohistochemistry was used to test the MMR status of both primary and matched metastatic tumors, and PCR analysis was performed to test MSI in patients with deficient MMR (dMMR) status. Results: A total of 369 patients were included. Of the 46 patients with MSI-high primary tumors, 37 (80.4%) also had MSI-high metastatic tumors, whereas 9 (19.6%) had microsatellite stable (MSS) metastatic tumors. A high concordance was found in patients with liver, lung, or distant lymph node metastases. Interestingly, the discrepancy was more likely to be limited to peritoneal (5/20) or ovarian (4/4) metastasis (chi-square test, P<.001). These organ-specific features were also found in the pooled analysis. Along with the change of MSI-high in primary cancer to MSS in metastatic cancer, lymphocyte infiltration decreased significantly (P=.008). However, the change did not influence survival; the median overall survival of MSI-high and MSS metastatic tumors was 21.3 and 21.6 months, respectively (P=.774). The discrepancy rate was 1.6% for patients with proficient MMR primary tumors. Conclusions: For patients with dMMR primary tumors, the concordance of MSI and MMR status in primary CRC and corresponding metastatic cancer is potentially organ-specific. High concordance is found in liver, lung, and distant lymph node metastases, whereas discrepancy is more likely to occur in peritoneal or ovarian metastasis. Rebiopsy to evaluate MSI-high/dMMR status might be needed during the course of anti–PD-1 therapy in cases of peritoneal or ovarian metastasis.

Background: Neoadjuvant anti–PD-1 therapy has shown encouraging efficacy in patients with deficient DNA mismatch repair (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer (LARC), which suggests its potential as a curative-intent therapy and a promising treatment option for organ preservation. We aimed to investigate the long-term outcomes of patients with dMMR/MSI-H LARC who experienced clinical complete response (cCR) after anti–PD-1 therapy. Methods: We retrospectively analyzed patients with dMMR/MSI-H LARC who achieved cCR and received nonoperative management following neoadjuvant anti–PD-1–based treatment from 4 Chinese medical centers. Patients were followed up for at least 1 year after they achieved cCR, their clinical data were collected, and survival outcomes were analyzed using the Kaplan-Meier method. Results: A total of 24 patients who achieved cCR and received nonoperative management from March 2018 to May 2022 were included, with a median age of 51.0 years (range, 19.0–77.0 years). The median treatment course to reach cCR was 6.0 (range, 1.0–12.0). Fifteen patients (62.5%) continued their treatments after experiencing cCR, and the median treatment course was 17.0 (range, 3.0–36.0). No local regrowth or distant metastasis was observed in a median follow-up time of 29.1 months (range, 12.6–48.5 months) after cCR. The 3-year disease-free and overall survivals were both 100%. Conclusions: Patients with dMMR/MSI-H locally advanced or low-lying rectal cancer who achieved cCR following anti–PD-1–based therapy had promising long-term outcomes. A prospective clinical trial with a larger sample size is required to further validate these findings.